Hydraulic actuating mechanism for planers



June 18, 1935.

D H. WEST ET AL HYDRAULIC ACTUATING MECHANISM FOR PLANERS Filed Sept.28, 1931 6 Sheets-Sheet l i f 5 WM r June 18, 1935. D. H. WEST Er AL2,005,018

HYDRAULIC ACTUATING MECHANISM FOR PLANERS Filed Sept. 28. 1931 6Sheets-Sheet 2 O jaw-11%,, M

June 18, 1935. D. H. WEST ET AL.

HYDRAULIC ACTUATING MECHANISM FOR PLANERS Filed Sept. 28, 19.71 6Sheets-Sheet 3 hnn - 45;, Ma hem June 18, 1935. WEST ET AL HYDRAULICACTUATING MECHANISM FOR PLANERS 6 Sheets-Sheet 4 Filed Sept. 28, 1951June 18, 1935. D, H. WEST ET AL HYDRAULIC ACTUATING MECHANISM FORPLANERS 6 Sheets-Shet 5 Filed Sept. 28, 1951 June 18, 1935. D. H. WESTE1 AL 2,005,018

HYDRAULIC ACTUATING MECHANISM FOR PLANERS Filed Sept. 28, 1951 6sheetssheet e 02: lye/1 2 70 Z 02a Aazzw Patented June 18, 1935 UNITED STATESPATENT OFFICE Donald H. West, Marlboro, and Kenneth 0. Monroe, Hudson,Mass., assignors to The Lapointe Machine Tool Company, Hudson, Masa, acorporation of Maine Application September 28, 1931, Serial No. 565,420

6 Claims.

This invention relates to mechanism for actuating the reciprocatingtable or carriage of a planer or other machine tool. The use of highspeed tools in such machines renders much higher 5 table speedsdesirable, in order to fully utilize the advantages of the improvedtools.

It is the general object of our invention to provide improvedtable-operating mechanism so designed that increased table speed isavailable 10 and that smooth and rapid reversal may be accomplished.

A further object is to provide actuating mechanism which may beconveniently adjusted to vary the speed of the cutting stroke, thereturn speed and the rates of deceleration and acceleration at thereversal of each stroke.

We also provide mechanism by which the permissible ratio of decelerationand acceleration are much increased, which result is facilitated byeliminating the reversal of heavy rotating parts.

Our invention further relates to arrangements and combinations of partswhich will be hereinafter described and more particularly pointed out inthe appended claims.

A preferred form of the invention is shown in the drawings, in whichFig. 1 is a side elevation of a planer embodying our improvements;

Fig. 2 is a diagrammatic plan view showing the hydraulic actuatingmechanism and connections, together with the control devices therefor,and

Figs. 3, 4, 5 and 6 are similar diagrammatic views illustratingdifferent operating conditions.

Referring to Fig. 1, we have shown a planer having a base ID on which atable T is guided for longitudinal sliding movement. A cylinder I3 ismounted in fixed position in the base I and a piston I4 is slidable inthe cylinder i3 and is connected by a piston rod l5 to the right handend of the table T, as shown in Fig. 2.

When oil or other liquid under pressure is admitted to the cylinderspace IS, the table T is moved to the right for an operative movement,carrying the work under a suitable tool K.

When liquid is admitted to the annular cylinder space I! surrounding thepiston rod IS, the table T is moved to the left at relatively highspeed.

Our improved planer is equipped with a suitable driving motor M whichcontinuously rotates a relatively large table-operating pump P and arelatively small control or pilot pump P. The planer is also providedwith an automatic reversing valve mechanism V, a speed control and maindifferential valve mechanism V, a control mechanism V for the pump P,and hydraulic tool feed mechanism D. The automatic reversing valvemechanism V may be operated as usual by dogs 20 mounted on the table Tand engaging an oifset arm 2| on the piston rod 22 of the reversingvalve mechanism V.

General operation prior patent to West, No. 1,722,832. The direction andrate of flow of oil to the cylinder I3 is controlled by reversing thedischarge of the pump P, 1

the connections between the pump and the cylinder remaining unchangedduring operation of the planer.

The auxiliary or pilot pump P is preferably of the same general type asthe pump P, but is arranged to automatically maintain constant pressurein its discharge pipe and the discharge is never reversed, although itmay be brought to zero after the predetermined pressure has beenattained and in case there is no demand on the pump.

The reversing valve mechanism V changes the connections to the pumpcontrol mechanism V and the mechanism W operates to reverse thedirection of flow of the pump P. The speed control and main differentialvalve mechanism V may be set manually for either fast or slow speedoperation of the cylinder on the cutting stroke, but without affectingthe speed of the return stroke.

Provision is also made for automatically raising the tool from the workon the return stroke and for feeding the tool after each cut. The toolfeeding mechanism D may be adjusted manually to feed at the beginning ofthe return stroke or at the beginning of the cutting stroke, as may bepreferred, and may be adjusted to vary the rate of feed.

The connections and operation of the pump control mechanism W are veryimportant, as they determine the rate of movement of the reversingmechanism for the pump P and thus determine the rate of deceleration andacceleration of the table T. flFm'thermore, these connections may beindependently adjusted to increase or decrease the rate of eitherdeceleration or ac- Pump mechanism As previously stated, the pumps P andP are preferably of the type shown in the West Patent #1,722,832 and maybe briefly described as follows:

The pump P comprises a casing (Fig. 2) having plurality of pistons 5|slidable in a rotating cylinder block 32 and connected to a plate 53,rotatably mounted in a tilting holder or cradle 34.

The cradle 34 is provided with segment gear teeth 55 engaged by a pinion55 mounted on a shaft 31 having bearings in the upper part of the casing35 and engaged by a rack bar 55 mounted on a rod 35 which is slidable ina bearing 45 and is connected to a piston 4| and cylinder 42 formingpart of the control valve mechanism V When the piston 4| is at one endof its path of travel, as shown in Fig. 2, the pump P will operate todischarge oil. into an upper discharge pipe 44, and when the piston 4|is at its opposite limit of travel, as shown in Fig. 3, the pump Pdischarges oil from a lower discharge pipe 45.

The piston 4| has only three operative positions, shown in Figs. 2, 3and 6 respectively, and these positions represent cutting, return andneutral operating conditions.

The pipe 44 is connected to the left hand end of the cylinder I3, asshown in Fig. 2, \and is provided with a check valve 41 opening towardthe cylinder I3. The pipe 44 is also preferably provided with a by-pass45 having an adjustable shut-off valve 45 by which the rate of dischargefrom the cylinder space I5 may be controlled, so that a suiiicient backpressure may be provided on the return stroke to insure smooth workingof the table.

A pipe 55 connects the pipe 44 to the speed control valve mechanism V towhich the lower pump connection 45 is also attached. A branch connection5| between the pipes 44 and 45 is normally closed by a shut-off valve52.

The right hand end of the cylinder i5 is connected by a pipe 54 to thespeed control valve mechanism V and is provided with a check valve 55,by-pass 55 and adjustable shut-off valve 51, all as previously describedin relation to the pipe 44.

When the mechanism is set for a slow speed cutting stroke, as shown inFig. 2, oil is delivered from the pump P through the pipe 44 and pastthe check valve 41 to the cylinder space I5 in the cylinder I3, whilethe annular space I! in the cylinder I3 is connected through the pipe 54and by-pass 55 to the speed control valve mechanism V.

On the return stroke, the parts take the position indicated in Fig. 3,and the flow of oil is reversed, entering the annular cylinder space I1and being discharged from the cylinder space I5.

Reversing valve mechanism The reversing valve mechanism V comprises acasing 55 having a cylindrical opening 51 in which pistons 52, '53 and54. are slidable, these pistons being mounted in spaced'relation ontherod 22 previously described.

The pilot pump P delivers oil at constant pressure through a dischargepipe 55 (Fig. 2) to a port 51 in the casing 01 the cylinder 5|. Adischarge port 55 in the cylinder 5| is connected by a discharge pipe 55to an over-flow or storage tank S. The discharge pipe 55 may be providedwith a gauge 15 and strainer II Ports l2 and I5 in the cylinder 5| areconnected together by a branch pipe 14 and are connected to one end ofthe cylinder 42 of the pump control mechanism W by a pipe 15 having anadjustable needle valve 15 mounted therein.

Additional ports 55 and 5| in the cylinder 5| are connected by branchpipes 52 and I55 and these branch pipes are connected by a pipe 55 tothe opposite end of the cylinder 42. The pipe 55 is similarly providedwith an adjusting or needle valve 54.

Ports 55 and 51 in the cylinder 5| areconnected by additional pipes 55and 55 to intermediate ports in the side 01. the cylinder 42. A pipe 55branches 01! of the pipe 55 and leads to one end or the upper cylinderin the'speed control. and main dinerential valve mechanism V, while apipe 5| branches oi! oi the pipe 55 and leads to the opposite end or thesame upper cylinder in the valve mechanism V.

Additional branch pipes 52 and 55 lead oiT of the pipes 55 and 55 andare provided with adiusting or needle valves 54 and 55. The pipes 52 and55 are joined to a common pipe 55 which connects to an opening at thelower side of the casing 35 01. the pump P. A corresponding opening atthe upper side of the casing is connected by a pipe 51 to a pipe 55,which in turn is connected to the discharge or surge pipe 55 oi! thestorage tank S.

Pilot pump and control connections The pipe 55 has an additionalconnection I55 to the tank S and also has a connection |5| to the underside of the casing of the pilot pump P. An additional connection I52leads to the left hand end of the control cylinder I55 tor the constantpressure or pilot pump P'. The opposite end of the cylinder I55 isconnected by a pipe I54 to the discharge pipe 55 ot the pump P.

A pipe I55 leads from the casing to the intake of the pump P, so thatthe oil supply oi the pump P is drawn from the tank S through the branchpipe I55, pipe 55 and branchpipe IN. The latter pipe delivers the oil tothe lower part of the casing of the pump P' through which casing the oilflows to the pipe I55, by which the oil is dellveredto the intake 01',the pump P. The discharge of the pump P is delivered through the pipe 55to the reversing valve mechanism V.

A piston H5 is slidable in the cylinder I53 and isconnected-by a rod IIIto a rack ||2, engaging a pinion 3 adapted to rock the output controlcradle II 4 of the pilot pump P.

A spring I I5 acts against a collar I6 on the rod ill to move the piston5 to the right in Fig. 2, or in a direction to increase the discharge orthe pump P. A portion of the oil discharged from the pump P is deliveredthrough the pipes 55 and I54 to the cylinder I55 and tends to move thepiston M5 to the left or in a direction to decrease the discharge or thepump.

By suitably selecting or adjusting the spring 5, the pressure of the oilagainst the piston I I5 will balance the pressure of the spring 5 at apredetermined discharge pressure and this predetermined pressure will becontinuously maintained by the pump P. If oil is discharg d through thepipe 55 in sumcient quantity to cause a drop in pressure, the spring II5will overcome the pressure on the piston I I0 and will move the rack H2in a direction to increase the discharge of the pump, thus bringing thepressure back to the predetermined normal.

Speed control and main diflerential valve mecha- 9| previously describedI nism The speed control and main differential valve mechanism Vcomprises a casing I20 having an upper cylinder I2I and a lower cylinderI22. Three pistons I23, I24 and I25 are mounted in spaced relation on apiston rod I25 in the upper cylinder I2I, and two pistons I21 and I28are similarly mounted in spaced relation on a piston rod I29 slidable inbearings at the ends of the lower cylinder I22 and connected for manualoperation by a hand lever I30 (Fig. 1).

The rod I29 is also provided with a slightly enlarged portion providinga shoulder I3I which limits movement of the rod and pistons to the leftin Fig. 2.

The pipe 54 connects the space H (Fig. 2) of the cylinder I3 to a portI33 which opens into both the upper and lower cylinders I2I and I 22.Similarly, the pipe 45 connects with a port I34, also opening into bothcylinders, and a pipe I36 is connected at one end through the pipe 99 tothe storage tank S and at its lower end through branch connections I31and I38 to ports in the upper cylinder I2I.

The branch pipe 50 previously described also connects the upper pumpdischarge pipe 44 to an additional port in the upper cylinder I2I.

When the rod I29 and pistons I21 and I28 are in the position shown inFig. 2, the piston I4 and table T wil be moved at relatively slow speed,as the discharge of the pump P will be delivered through the pipe 44 tothe cylinder space I8, while the annular space H at the opposite end ofthe cylinder will be connected through the pipe 54, ports I33 and I34and pipe 45 to the intake of the pump P.

As the oil forced out of the cylinder space H is much less in amountthan the oil forced into the cylinder space I8, additional oil issupplied to the pump P from the storage tank S through the pipes 99 andI36, branch pipe I38 and pipe 45. The piston I4 is thus moved at therate at which the full discharge of the pump will fill the cylinderspace I5.

For high speed operation, (Fig. 4) the handle I30 is shifted to move thevalve rod I29 and pistons I21 and I28 to their left hand limit oftravel, thus connecting the pipe 54 through the ports I33 and I35 to theupper cylinder I2I and thence through the branch pipe 50 to thedischarge pipe 44 of the main pump P.

In this case, the oil discharged from the annular cylinder space I I isby-passed around to the cylinder space I6 and it is only necessary forthe pump P to supply oil equivalent to the difference in volume betweenthe space H and the space I6. Consequently a given amount of oildelivered by the pump to the space I5, being used in addition to thatby-passed around the piston I4, will produce substantially more rapidtravel of the piston I4 and table T than when the oil is not by-passed.

During a high speed cutting stroke, no part of the oil discharged fromthe cylinder space H will return to the pump P and the oil supply of thepump must be obtained through the pipes 89 and I38, branch plpeI38,upper cylinder III and pipe 8.

Return stroke The position of the differential valve in the a uppercylinder I2I of the valve mechanism V is determined by the applicationof pressure at the ends of the valve through the pipes 94 and During theoperative stroke, pressure will be applied through the pipe 9I, asindicated in Fig. 2, maintaining the upper piston valve in its righthand position, but on the return stroke pressure will be applied throughthe pipe 90, as indicated in Fig. 3, forcing the upper piston valve tothe left.

This movement of theupper or differentialvalve is timed to take placewhen the piston 4I of the reversing valve mechanism W is Just passingneutral or mid-position, at which time the pump discharge issubstantially zero. The rack 38 and gear 38 are in such mechanicalrelation to the piston 4I that when the piston is in mid-position, thecradle 34 is in neutral or no-discharge position as shown in Fig. 6. Assoon as the piston 4| moves beyond mid-position in either direction, oneof the pipes 88 or 89 is uncovered and the valve in the upper cylinderI2I is shifted before substantial movement of the cradle 34 from neutralposition can occur. This is an ex'- tremely important feature of ourinvention, as serious results might be obtained if the differentialvalve was shifted while the pump was discharging in either direction.

The parts are shown in Fig. 3 as positioned for the return stroke aftera high speed cutting stroke. Under these conditions, the pump Pdischarges through the pipe 45, upper part of port I34, port I 33 andthe pipe 54 to the right hand end of the cylinder I3, while the lefthand end. of the cylinder is directly connected through the pipe 44 tothe intake of the pump P.

As the volume discharged from the cylinder I3 through the pipe 44 isgreater than the volume supplied to the cylinder through the pipe 54,the surplus oil is delivered through the branch pipe 50, upper cylinderI2I to the branch pipe I31, and thence through the pipes I35 and 93 tothe storage tank S.

The opposite ends of the lower cylinder I 22 are connected throughpassages I40 to ports in the upper cylinder which are connected throughthe branch pipes I31 and I38 to the storage tank. This permits out-flowof oil at the ends of the cylinder as the lower piston valve is shifted.

The operation of the valve mechanism for a return after a slow speedstroke is not shown in the drawings but is substantially identical withthe operation after a high speed stroke, the only difference being thatthe path of flow of liquid from the pipe 45 to the pipe 54 is directlythrough the upper and lower parts of the port I34, instead of throughthe ports I34 and I33 successively as previously described. Nodifference in ultimate result is produced.

Tool feeding mechanism with adjustable stops I45 and I46, engagingopposite sides of a fixed abutment I41.

At its lower end, the piston rod I44 may be connected in any convenientmanner to operate the cross feed of the cutting tool.

In Fig. 2 we have indicated these connections as comprising a ratchetwheel I46 mounted on a cross feed shaft I49 and engaged by a double pawlIll mounted on the lower end of the valve rod I44. The pawl I50 may beset to operatively engage the ratchet I46 either on the upward stroke oron the downward stroke, as may be desired, and may be provided with anysuitable spring devices for holding it in yielding engagement with theratchet in either position.

A pipe I52 connects the lower end of the cylinder I42 to a controlcylinder I54 at about the middle of its length. The upper end of thecylinder I42 is connected by a branch pipe I55 to the upper endof thecylinder I54, and by a branch pipe I56 to a lower point in the cylinderI54.

Pistons I51, I58 and I56 are mounted in spaced relation on a piston rod.I60 extending upward through the cylinder I54 and manually adjustable tohigh, low or intermediate positions.

A pipe I62 is connected at one end to the discharge pipe 44 of the pumpP and at the other end to a port in the side of the cylinder I54 betweenthe ports for the pipes I52 and I55. A pipe I63 is similarly connectedat one end to the discharge pipe 45 of the pump P and at the other endto a port in the cylinder I54 between the ports for the pipes I52 andI56.

The cross feeding mechanism is shown in Fig. 2 in the position forfeeding just prior to the beginning of the cutting stroke. The valve rodI60 is in its raised position, and oil under pressure is delivered fromthe pump discharge pipe 44 through pipe I62, control cylinder I54, andpipe I52 to the lower end of the cylinder I42, giving the piston I43 anupward feeding stroke as the pressure is built up in the discharge pipe44 as the pump P is reversed and just prior to the working stroke.

When the pump P is again reversed at the end of the cutting stroke,pressure in the pipe 45 will be transmitted through the pipe I63,cylinder I54, and pipes I56 and I55 to the upper end of the cylinderI42, thus forcing the piston I43 downward and giving the pawl I50 anidleor return movement. The amount of feed may be controlled by thesetting of the stop nuts I45 and I46.

If the valve rod I60 is moved to its middle or neutral position, thepistons I51 and I56 close the port openings of the pipes I62 and I63,and the cross feed is thus rendered inoperative.

If the valve rod I60 is moved to its lowest position, oil under pressurewill be delivered from the pipe I62 through the pipe I55 to the upperend of the cylinder I42 to effect an idle return movement just prior tothe beginning of the cutting stroke, and will be delivered from the pipeI63 through the pipe I52 to the lower end of the cylinder I42 to effecta feeding movement just prior to the beginning of the return stroke.Consequently, feed will take place at the beginning of the return strokerather than at the beginning of the cutting stroke.

By reversing the setting of the pawl I50, cross feed in the oppositedirection may be attained.

Tool lifting device It is desirable under some conditions that thecutting tool K be lifted from the work during the return stroke, so thatthe edge of the tool will not be dulled or broken by being dragged overthe surface of the work. For this purpose we provide a small cylinderI10 (Fig. 2) mounted in the tool holder or clapper HI and having apiston I12 mounted on a plunger I13 which projects through the outer endof the cylinder I10 and engages the cross head I14.

A pipe I15 connects the cylinder I10 to the pipe I63 which in turn isconnected to the pipe 45 to which oil is delivered under pressure duringthe return movement of the table.

Consequently, whenever pressure is applied in the pipes 45 and I63,pressure will also be applied through the pipe I15 to the cylinder I10,forcing the piston I12 into the cylinder against the pressure of aspring I16.

As the cross head I 14 cannot yield, the tool holder or clapper I" isthereby swung outward, raising tool K away from the table T during thereturn stroke.v

A control valve I16 provides for adjustment of the rate of movement ofthe tool holder HI and a by-pass I11 with a check valve I15 permitsquick seating of the tool holder before the cutting stroke.

Operation Having described the details of construction of our improvedmechanism, the method of operation is as follows:

' The mechanism is first set for a fast or slow speed cutting stroke bymanual adjustment of the handle I30, by which the speed control valve inthe lower cylinder I22 of the valve mechanism V is adjusted. The feedcontrol valve rod I60 is also set to effect the intermittent feed justprior to the return stroke or just prior to the cutting stroke, as maybe desired under existing operating conditions.

Disregarding for the present the devices by which deceleration andacceleration are controlled, we will assume that the reversing valve Vis in the'position shown at Fig. 2, with the table T moving to theright. It will be seen that oil at constant pressure will be deliveredby the pilot pump P through the pipes 66 to the reversing valve cylinder6I and thence through the pipes 14 and 15 to the right hand end of thecontrol cylinder 42, forcing the piston 4i to its left hand limit oftravel and adjusting the main pump P for maximum predetermined dischargethrough the pipe 44. i

This effects a working stroke of the table T at high or low speed, inaccordance with the setting of the valve rod I26 by handle I30. At thesame time, the pipe 33 from the left hand end of the control cylinder 42is connected through the cylinder 6i and pipe 69 to the storage tank S.At the end of the cutting stroke, the reversing valve V is shifted tothe position shown in Fig. 3, so that oil under pressure is deliveredfrom the pilot pump P through the pipe 66, cylinder 6i and pipe 33 tothe left hand end of the control cylinder 42.

This moves the piston 4I to the right and reverses the discharge of thepump P, so that the pump now discharges through the pipe 45 to the righthand end of the cylinder I3, causing a return movement of the piston I4and table T. At the same time, the pipe 15 from the right hand end ofthe cylinder 42 is connected through the cylinder 6i and pipe 69 to thestorage tank S.

It will be noted that whenever oil is delivered to either end of thecylinder I3 by the pump P,

this oil flows freely past the check valve 41 or 58, but that when oilflows from the cylinder l8 to the pump P. this flow is resisted by thecheck valves and must take place through the by-pass 48 or 98, such flowbeing regulated by the ad- Justing valves 49 and 51. Consequently, anydesired back pressure can bemaintained on the piston 14, so as to inducea smooth and even motion in either direction.

Operation of pump control mechanism W A very important part of ourinvention relates to the operation of the mechanism V, which effects thereversal of the pump P and consequently the deceleration andacceleration ofthe table T.

During the cutting stroke, the piston 4| of the control mechanism W isin the left hand position shown in Fig. 2, and the reversing valvemechanism V is also. in the position shown in Fig. 2.

At the end of the cutting stroke, the arm 2| is engaged by one of thedogs 28 and the reversing valve is moved to the right toward theposition shown in Fig. 3. As the reversing valve starts to move, oilunder pressure is first admitted through the branch pipe I89 and pipe 88to the left hand end of the cylinder 42.

As the port for the pipe 88 in the cylinder 42 is closed by the piston4|, the full oil pressure is applied to the left hand side of the piston4| but the rate of flow to the cylinder 42 is controlled by the settingof the regulating valve 84.

The right hand end of the cylinder 42 is still connected to the oilsupply through the pipe l8 and branch pipe 14, but the port to the pipe89 is open so that oil can flow past the regulating valve 95 to the pipe98 and thence through the casing of the pump P to the storage tank S.Consequently the oil pressure in the right hand end of the cylinder 42is somewhat reduced and the piston 4| begins to move toward the. right,the rate of movement being controlled by the setting of the valves 84,I8 and 95.

Pressure is maintained in the pipe 9| and the piston valve in the uppercylinder |2| of the valve mechanism V' remains in the position shown inFig. 2, with the pipe 99 connected to the return.

Meanwhile, the reversing valve continues its travel to the right untilthe port 81 for the pipe 89 is uncovered, thus connecting the pipes 89and 98 to the return pipe 89, which connects directly to the storagetank S and allows the oil to return without passing through theregulating valve 95.

In the meantime, the piston 4| has been moving toward the right. Duringthe first part of its stroke this movement was due to the net differencein pressures on the two sides of the piston 4| and was controlled by thethree valves 8t, 95 and it.

By the time the pipe 89 was connected to the return pipe 69, the piston4| had been moved far enough to shut off the connection to the pipe 89from the cylinder 42.

The pressure in the pipe 9| and the left hand end of the cylinder |2|was thus relieved, and a slight dwell of the reversing mechanism of thepump P occurs, as there is balanced pressure on the piston ti.

A slight continued movement of the reversing valve causes the piston 82to shut off the oil supply to the branch pipe M and a slight furthermovement brings the valve to the final position with the pipe 18connected to the return pipe 89,

-as shown inTig. 3.

During the continuedmovement of the piston 4| to the right, the oilejected from the cylinder 42 is all forced to escape through the pipe 15and is controlled by the valve 16. 2

Furthermore during the latter part of the stroke of the piston 4|, theconnection from the left hand end of the cylinder to the pipe 88 isopened. thus reducing the effective pressure to move the piston 4|, as aportion of the oil under pressure escapes past the valve 94 and throughthe pipe 92 to the casing of the pump P and thence to the storage tank.

when the pipe 88 is uncovered, oil under pressure acts through the pipe9|! to move the piston valve in the cylinder |2| to the left, reversingthe connections to between the pump P and the cylinder l3. This reversemovement of the valve in the cylinder |2| takes place when the pump a Pis in neutral position and there is no discharge found that a heavyplaner table or similar object can be decelerated or brought to restmore quickly than it can be accelerated or broiight up to speed in theopposite direction.

The branch pipes 92 and 93 and the regulating valves 94 and 95, taken inconnection with the adjusting valves 16 and 84, permit us to'cary therate of movement of the piston 4| during different parts of its traveland to cause the pump P to be brought to neutral and to be renderedoperative in the reverse direction in any desired time intervals.

Suitable provision is made for determining the setting 01' the pump Pfor discharge in each direction. In Fig. 2 we have indicated adjustablestop screws |8| and I82 positioned for engagement by a lug or projectionI83 on the rack 38. By adjusting the screws |8| or I82, the limit ofmovement of the rack in each direction may be determined, which in tuiynwill determine the extreme positions of the rocking cradle 33 and willthus determine the rates of discharge of the pump P.

It will be evident that this rate of discharge may be independentlyadjusted for each direction of operation, so that the speed of the tableT during its working stroke and also during its return stroke may beindependently determined. Under ordinary conditions, the return strokewill be made at substantially higher speed than the cutting stroke.

The operation of our hydraulic operating mechanism may be convenientlystopped by manually moving the reversing valve V to its middle orneutral position, which causes the piston 4| to move to the middle orneutral position shown in Fig. 6, in which it will be seen that thepressures are balanced on the two sides of the piston 4| and that thepipes 88 and 89 are both closed by the piston 4|. After being moved tothis position, the piston 4| will remain indefinitely in neutralposition, as any movement of the piston in either direction wouldpartially uncover one of the pipes 88 or 89, thus reducing the pressureon the side from which movement had occurred, so that a reverse orreturn movement to-neutral position would immediately take place.Consequently the planer or other machine tool can be manually stopped inany position by moving the reversing valve V to mid-position, and willremain at rest until the valve V is manually moved to one or the otherof its operating positions.

Having thus described our invention and the advantages thereof, we donot wish to be limited to the details herein disclosed, otherwise thanas set forth in the claims, but what we claim is:-

l. Hydraulic actuating mechanism for a member connected to bereciprocated by relative movement of a cylinder and piston, saidmechanism comprising a reversible discharge pump having two flowopenings, means to continuously connect one opening to one end of saidcylinder, means to connect the other opening to the other end 01' saidcylinder, and means to effect discharge of said pump through one of saidflow openings to cause travel of said reciprocated member in onedirection and through the other flow opening to cause travel of saidreciprocated member in the other direction, said latter means beingcontrolled by said reciprocated member as it approaches a limit oftravel and comprising pump-reversing mechanism, a cylinder and pistonconnected to move said mechanism, and a plurality of separate devicesacting successively and automatically to determine difierent rates ofmovement of said latter piston in difierent portions 01' its strokeduring a single pump reversal.

2. Hydraulic actuating mechanism for a member connected to bereciprocated by relative movement of a cylinder andpiston, saidmechanism comprising a reversible discharge pump having two flowopenings, means to continuously connect one opening to one end 01' saidcylinder, means to .connect the other opening to the other end or saidcylinder, means to effect discharge or said Pump through one 0! saidflow openings to cause travel of said reciprocated member in onedirection and through the other flow opening to cause travel or saidreciprocated member in the other direction, said latter means beingcontrolled by said reciprocated member as it approaches a limit oftravel and including devices efiective to vary and control the rate ofdeceleration and the rate of acceleration of said reciprocated memberduring a single reversal thereof and to control each rate of changeindependent of the other rate.

3. Hydraulic actuating mechanism for a reciprocated member comprising avariable delivery reversible discharge pump and devices controlled iromsaid member for varying and reversing the discharge of said pump, saiddevices including a control cylinder and piston connected to reversesaid pump, and means by which the.

livery reversible discharge pump, and devices con-- trolled irom saidmember for varying and reversing the discharge oi said pump, saiddevices including a control cylinder and piston connected to reversesaid pump and meanslto variably control the rate of movement of saidcontrol piston in different parts of its stroke and 'by which apredetermined dwell at the middle portion 01' the stroke may beefl'ected during said pump reversal.

5. Hydraulic actuating mechanism for a reciprocated member provided witha cylinder and piston, one of which is connected to said mem- I ber,said mechanism comprising a variable delivery reversible discharge pumphaving discharge openings one of'which is' continuously connected to oneend of said cylinder and speed control valve mechanism through which theother of said discharge openings is connected to the opposite end ofsaidcylinder, means controlled from said reciprocated member andeffective to reverse the direction of discharge of said pump at eachlimit of travel of said reciprocated member, and means to separatelycontrol the rate of deceleration and the rate oi acceleration of saidreciprocated member during a single pump reversal, whereby either rateof change may be independently varied during said single reversal.

6. Hydraulic actuating mechanism for a member connected to bereciprocated by relative movement of a cylinder and piston, saidmechanism comprising a reversible discharge pump, means to reverse thedirection of discharge 01' said pump, a storage for excess liquid, aby-pass connection from one end of said cylinder to said storage, andautomatic means comprising a pressure operated valve, said latter meansbeing ef- Iective to open said by-pass connection 'at one limit oftravel of said piston and when the pump is substantially in zerodischarge position.

DONALD H. WEST.

KENNETH C. MONROE.

